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The chosen plan for our case study is a network mixture design consisting of 21 mixtures. The application of this method has proven to be immensely useful in studying the influence of composition parameters (composite design) and the utilization of various types of mineral additives (mixture design). The application of the Design of Experiments (DOE) method, based on a statistical approach, allowed for a better understanding of the effect of formulation parameters, including the proportion of alluvial sand (75%), dune sand (25%), the total amount of sand kept at constant percentages, the dosages of brick powder, limestone filler and ceramic powder (all varying from 0 %, 20 %, 40 %, 60 %, 80 %, and 100 %), while keeping the dosage of superplasticizer and the water/binder ratio constant. This approach helped to understand the interactions between these parameters and their impact on the process. Mathematical models relating the variations of these parameters to the workability and compressive strength of such concrete mixtures have been established. The results obtained show that the workability of SCSC (expressed by slump flow and V-funnel flow) improves with the increase in the dosage of limestone filler (FC), brick powder (PB), and ceramic powder (PC), with element having a different impact, be it alone or in a combination. Moreover, they all improved the behavior of SCSC in both the fresh and hardened states. The experiment shows that increasing the proportions of FC and PC in the mixture, whether linear, binary, or ternary, leads to a significant improvement in compressive strength. Furthermore, better strength is observed in the ternary mixture at 28 days, with a strength of 43 MPa, with the following proportions (FC 70%, PB 20%, PC 10%). Finally, the result at 180 days of 48 MPa confirms the following proportions (PC 60 %, FC 30 %, PB 10 %) The compliance of some SCSC compositions was tested according to the recommendations of the French Association of Civil Engineering. [ABSTRACT FROM AUTHOR]

Owing to their high intrinsic properties, limestone fines (LF) seems to be a good replacement material of cement and/or sand, elaborating thus a new concrete without affecting its performances and properties. The present work aims at using, however, this natural material as an alternative cement or sand replacement, and investigating its influence on self-compacting concrete (SCC) properties at fresh and hardened states. Achieving this, several parameters have been examined, in terms of compressive strength, water permeability, chloride-ion penetration, gas permeability, water porosity and sorptivity. A total of 11 SCC mixes samples have been produced in two series, each one with different rate substitution (0%, 5%, 10%, 15%, 20% and 25%) of sand and cement. Our experimental data revealed the incorporation of LF up to 20% in SCC as partial replacement of sand and cement at fresh state, led to appreciable properties results. Nevertheless, at hardened state, at 15% for sand replacement an increase in compressive strength and a decrease in the water and chloride-ion diffusion, while an increase in the gas diffusion has been registered. And for cement replacement at 5%, an improvement in compressive strength and chloride ions diffusion was noted, whereas the water permeability and the gas diffusion decreased at 15% of LF substitution, where these results are widely discussed and explained in this paper. [ABSTRACT FROM AUTHOR]

This paper presents an experimental investigation of the effect of concrete compressive strength, strengthening ratio and corner radius on the behavior of small-scale square columns wrapped with carbon fiber-reinforced plastic (CFRP) materials. A total of 39 specimens (150 × 150 × 300 mm) wrapped with one, two, and three plies of CFRP wraps were tested. In addition to the FRP jacket thickness, the effect of three different concrete mixes and four cases of corner radius were examined. The effective circumferential CFRP failure strain and the effect of the effective lateral confining pressure were investigated. The obtained results show that the CFRP reinforced columns provide a significant increase in ultimate conditions (strength and ductility) compared to the case of the unconfined specimens. It can be seen that higher concrete compressive strength and lower strengthening ratio reduce the effect of confinement with CFRP material. The test results demonstrated that the corner radius ratio is in direct proportion to the increase in confined concrete strength. A new model is presented to predict the compressive axial strength and corresponding strain of CFRP-confined columns based on the effective lateral strain of FRP material. [ABSTRACT FROM AUTHOR]

Superplasticizers have become an integral ingredient in the formulation of concretes. After 40 years, their use and dosage remain uncertain due to variations in their compositions and those of cement. In addition, the substitution of cement by supplementary cementitious materials having different chemical compositions exacerbates the problem without counting the multiplicity of superplasticizers to choose from. The present work consists of a study of the rheological and mechanical properties of cementitious systems containing slag and various types of superplasticizers. The tests were carried out on pastes, mortars and concretes incorporating slag in partial cement replacement and four superplasticizers types, polynaphthalene sulphonate (PNS) and three polycarboxylates (PC). The results of this study demonstrate that the viscosity and the yield stress increase with the rate of incorporation of the slag. The air increases with the polycarboxylates but this effect is less perceptible in the presence of the slag. Polycarboxylates improve workability more than PNS. The use of polycarboxylates reduces the viscosity and the yield stress. The compressive strength of concretes containing slag is low at early age but high at long run. They exhibit good resistances to scaling. The permeability to chloride ions is considerably reduced in the presence of the slag independently of the type of superplasticizer, suggesting good durability of these concretes in potentially aggressive external environments. [ABSTRACT FROM AUTHOR]

This paper proposes an improved model for the reinforced concrete shear walls. The main contribution of this work is to provide a comparison between the proposed numerical model and an existed experimental test. It indicates the necessity of performing more complex numerical simulations, in order to describe the behaviour of L-shaped walls. To validate the accuracy of the proposed model, an investigation has been carried out in two parts. In the first part, the numerical model is developed by ANSYS to predict the cyclic behaviour of the L-shaped reinforced concrete walls, which has been designed according to the Algerian seismic design codes. The second part reports a numerical investigation that evaluates the behaviour of L-shaped walls by comparing the proposed model with the experimental tests. The results of this study demonstrate that the deformation by inflection at the base of the L-shaped reinforced concrete shear walls is dominant and occupies nearly eighty percent of the total deflection. The established model constitutes a practical tool for developing and reviewing the conditions of the reinforcement stipulated in the design codes. [ABSTRACT FROM AUTHOR]

Nowadays, information about geotechnical parameters and future stability of soil is highly demanded by geotechnical laboratories and companies. The use of geotechnical information systems integrated in a GIS offers a better manipulation of the geotechnical parameters of different sites for a general exploitation of storage, manipulation, management and analysis of geotechnical data. The aim of the current research is to present the results of studies developed to set up a geotechnical database for Algiers region using «Géo-Base» information system developed within the framework of this research and integrated in a GIS through a descriptive statistical analysis of mechanical and geophysical identification parameters of velocity measurements collected from 1200 survey profiles located on 80% of the surface of the region. The visualization of geotechnical maps of bearing, consolidation, settlement, swelling of soils at any depth of Algiers region are obtained by manipulating the system technology produced as part of this research. These results are very helpful to builders, planners, researchers and engineers in their future work; they will help them making better decisions and producing safer and more economical designs. Furthermore, this research allows establishing the first geotechnical map of Algiers region. [ABSTRACT FROM AUTHOR]

At the beginning the twenty-first century, a lot of high-level methods have become available in geotechnical engineering in order to deal with the complexity and heterogeneity encountered in soil, Statistical modeling (i.e. regression analysis method) was used to estimate the relationships among two or more variables, however in the early nineties an application of a new system emerged which gave excellent results in solving a lot of problems by learning from the available data so-called "artificial neural network". The aim of this study is to apply both methods, nonlinear regression analysis and artificial neural networks in order to predict geotechnical parameters from standard penetration test in all soil's types; Comparison of the results using correlation's coefficient (R) and Root Mean Squared Error (RMSE) is done between both methods; About 400 samples, over 65 boreholes in the Algiers area have been collected and were used in this study, The results show the superiority of ANN method in predicting data that seems closer to experimental values compared to NRA method. [ABSTRACT FROM AUTHOR]